docs: def parse_shebang(bytesio):
      """Parse the shebang from a file opened for reading binary."""
      if bytesio.read(2) != b'#!':
          return ()
      first_line = bytesio.readline()
      try:
          first_line = first_line.decode('UTF-8')
      except UnicodeDecodeError:
          return ()
  
      # Require only printable ascii
      for c in first_line:
          if c not in printable:
              return ()
  
      cmd = tuple(_shebang_split(first_line.strip()))
      if cmd[0] == '/usr/bin/env':
          cmd = cmd[1:]
      return cmd